tsa_rfc3161 1.0.2

This is a TSA (Time Stamping Authority) client/library RFC3161 for Flutter apps. With it, you can timestamp any files or any text message

Flutter TSA (Time Stamping Authority) client rfc3161

tested on macos and android configurations with digicert and certigna tsa (fails with flutter web if TSA host does not provide CORS header)

import 'package:dio/dio.dart';
import 'package:tsa_rfc3161/tsa_rfc3161.dart';

// ...


     TSARequest tsq = TSARequest.fromFile(
          filepath: file.path,
          algorithm: TSAHashAlgo.sha512,
          nonce: nonceValue,
          certReq: true);
          
      // for a string use 
      // TSARequest tsq = TSARequest.fromString(s: "yannick", algorithm: TSAHashAlgo.sha512);
      
      Response response = await tsq.run(hostname: "http://timestamp.digicert.com");

      if (response.statusCode == 200) {
        TSAResponse tsr = TSAResponse.fromHTTPResponse(response: response);
      }
    

Note 1

tsq.asn1sequence.encodedBytes is similar to the content of file.digicert.tsq generated by openssl

openssl ts -query -data file.txt -no_nonce -sha512 -cert -out file.digicert.tsq

Note 2

the content of response.data is similar to the content of file.digicert.tsr generated by digicert's http server

curl -H 'Content-Type: application/timestamp-query' --data-binary '@file.digicert.tsq'  http://timestamp.digicert.com > file.digicert.tsr

Note 3

authentication is available

 Response response = await tsq.run(
          hostname: "https://timestamp.dhimyotis.com/api/v1/",
          credentials: "$user:$password");

Note 4

TSAResponse tsr = TSAResponse.fromHTTPResponse(response: response);
        tsr.write("test.tsr");

you have now a test.tsr you can look with a openssl cli command

        $ openssl ts -reply -in test.tsr -text provides
        
        Version: 1
        Policy OID: 2.16.840.1.114412.7.1
        Hash Algorithm: sha512
        Message data:
            0000 - 89 bd 94 b7 92 4b 2f 16-d8 c5 c0 0f 11 02 12 b1   .....K/.........
            0010 - bb b1 5a bb 72 7d be 06-33 bf 7d d0 9f 6f d6 07   ..Z.r}..3.}..o..
            0020 - 02 4d a3 df d6 7b cf c7-89 e2 2f 2d d9 fa 9b c3   .M...{..../-....
            0030 - 39 9a d4 34 11 e1 11 d8-c6 7b a7 a0 b4 96 42 2d   9..4.....{....B-
        Serial number: 0x4194EF54150D2496B2C3F1A78D82C41B
        Time stamp: Sep  7 08:37:47 2024 GMT
        Accuracy: unspecified
        Ordering: no
        Nonce: 0x0191CBA1D914
        TSA: unspecified
        Extensions: